The present invention relates to a capacitor discharge ignition system for a multicylinder internal combustion engine.
A conventional capacitor discharge ignition system for a multicylinder internal combustion engine necessitates an exciter coil for charging the capacitor and a signal coil for supplying a turn-on signal to a thyristor which enables discharge of the capacitor. The exciter coil and the signal coil are provided in a multipolar magneto AC generator driven by the engine. The signal coil provided in a multipolar generator produces a turn-on signal a plurality of times during one revolution of the crank shaft of the engine so that a spark occurs at the ignition plug of each cylinder a plurality of times per revolution of the crank shaft. The fact that a spark occurs a plurality of times per revolution is particularly undesirable with a four-cycle engine because such occurrence will reduce the engine output. Another conventional ignition system employs a special signal source which is adapted to produce a signal once per revolution. However, signal output produced by such a signal source is of a short duration, so that it places a limitation to the range of ignition angle variation with engine speed which is often required.